According to the news we are hearing from Slashdot and other sources, Apple has finally made the decision to move their chip fabrication from Samsung, for fairly obvious reasons, with TSMC being the lucky fab that will get their business. They are starting with the current A6X chip, shrinking it to 28nm for the initial run, with the contract for producing the new A7 series dependant on the success of TSMC's trial run. As the 28nm node is quite familiar to TSMC, barring any production issues that limit availability, they are very likely to win the contract.

"The test will kick off in Q1 2013, The China Times reports, with TSMC producing a new, 28nm version of the existing 32nm A6X that Samsung has been producing for the full-sized iPad 4th-gen; the smaller chip, which will likely be more power efficient as well, will debut in a new iPad 5th-gen and iPad mini 2."